Developer units, electrophotographic apparatuses, and methods of supplying developer material to photoconductive members are disclosed.
In a typical electrophotographic process, a photoconductive member with a photoconductive layer is charged. The photoconductive member is exposed to selectively discharge areas of the photoconductive layer, while maintaining charge in other areas corresponding to image areas of an original document. This process records an electrostatic latent image of the original document on the photoconductive layer.
The latent image is developed by depositing developer material containing toner on the photoconductive layer using a developer housing structure. The toner is attracted to the charged image areas to produce a visible toner image on the photoconductive layer. The toner image is then transferred from the photoconductive member to a copy sheet. The toner is subjected to heat and pressure conditions effective to permanently affix the toner image to the copy sheet.
In developer housing structures that are designed for trimming developer material at the top of a magnetic roll, the trim position is typically located within about 135° of the pick-up position with respect to the outer surface of the magnetic roll. In such “top trim” developer units, the magnetic characteristics of the portion of the magnetic roll between developer material pick-up and trim positions can be optimized for trimming purposes.
It would be desirable to provide developer units suitable for use in electrophotographic apparatuses that are not constructed for trimming the developer material at the top of the magnetic roll, and can supply developer material to photoconductive members uniformly and at a desired rate.